The function of elastic couplings used between wagons in trains employing Talgo technology is to transmit longitudinal loads. These couplings are formed by two supports made of cast steel, one screwed to each end of the adjacent wagons.
The end or head of one of the supports of the coupling is curved, and the end or head the other support is flat, which allows certain rotation between wagons. The heads of the supports are attached to one another by an intermediate pin (also referred to as draw bolt) as well as by elastic parts to assure the draw and correct operation under normal use conditions.
To assure compliance with structural passive safety requirements in the event of various collision scenarios, it is necessary to include a certain ability to absorb energy between two adjacent wagons. This absorption must assure that no structural deformation of vehicles occurs such that it may compromise the interior compartment intended for passengers.
Due to the location of the elastic coupling as a rigid element between two wagons, in many Talgo trains today this absorption of energy is done as a result of the failure of the connection elements between support and structure. There is included behind the support an absorption element for absorption by deformation, which absorbs energy while the support is gradually introduced into the vehicle structure.
This configuration has the drawback of requiring free space inside the wagon and an additional element for absorbing energy.